The present invention relates to a locking device which consists of a lock and a key and which has tumblers that can be brought into a release position by the key.
Such locking devices are known. They can be formed, for instance, of locking cylinders which can be locked by flat keys or else also of locking devices which are operated with magnetic keys.
All of these locking devices share the common feature that while the number of locking combinations is frequently considerable, this number however, could be further increased in order to increase security. Particularly with respect to locking systems having master and specific keys there is a need to make available in a locking system a large number of keys which have different access authorizations. Such locking systems frequently have the disadvantage that the main master key which can be used for all locks of the locking system has only a relatively simple coding. In the case of locking devices which are used by continuously changing users (for instance, in hotels), it is necessary to ensure that the previous user cannot easily obtain a copy of the key, which would raise the possibility of his unauthorized access into the room inhabited by the subsequent user.
In many known locking devices an increase in the number of locking combinations also means an increase in the structural size of the key, which has a detrimental effect on convenience.
It is therefore an object of the present invention to create a locking device of the aforementioned type with which the number of locking combinations is increased without enlarging the structural shape of the key. In particular, there also exists an emergency key which, in emergency situations, permits opening the lock, and it is therefore necessary to ensure in the case of systems with continuously changing users that unauthorized actuation of the lock cannot be effected. Furthermore, misuse of the emergency key should be made difficult and the possible uses for the locking should be increased.